Sunday, November 13, 2011

An Anhinga sitting on a nest...

I almost missed this male Anhinga sitting on a nest. With his dark head held skyward, he bordered on invisible. You would think a big black and white bird would stand out in a sea of green leaves, but he didn't. His upward tilting head must have tricked my brain into thinking it was a branch and his dark feathers were shadows, but I was lucky because it was a hot day, and the fluttering of his gular pouch gave him away. The movement, made to help regulate his body temperature, was just enough to bring my eye back to his location....and there he was. Wow! My first nesting Anhinga atPinckney Island...

An incredibly beautiful bird, this male Anhinga sat patiently on the nest incubating eggs. Males have mostly black body plumage. During the breeding season they develop a shaggy crest and mane, which are not apparent in this photo, but you can see the "filoplumes" on the sides of the face and neck. These feathers are silky and almost hairlike.

Anhingas are aquatic birds that do their hunting under the water. With their necks coiled back, they hold their bills open a little, so when they do strike with those sharp and pointed bills, they leave two puncture marks. After Anhingas eat, they climb up on a branch and open their water-logged wings to dry.

The ability of an Anhinga to strike out with lighting speed to impale its prey on its sharp bill while underwater is because of a hinge-like mechanism between the eight and ninth cervical vertebrae, and a keel on the underside between the fifth and seventh cervical vertebrae that muscles attach to. When this hinge-like mechanism is sprung, the muscles propel the bill forward like a spear being thrown (similar to herons and egrets). I wanted to see what this looked like and found a very cool drawing of a skeleton of an Anhinga's neck showing the muscles and hinge from 1913--click here for the drawing (sources: "National Geographic Reference Atlas to the Birds of North America," Mel Baughman, pg. 64--one of my favorite reference books, and a Wikipedia article on Darters, here.)

Note: The drawing of the Anhinga's spine is from "Die Vogel: Handbuch der Systematischen Ornithologie, Volume 1," by Anton Reichenow. Click here for a link to the book. If you speak German and like old pen and ink drawings, you'll like looking through the book.

A female Anhinga perches on a limb. Females and juveniles have buff-colored heads, necks and chests.

Look at those feet! I would never have guessed that Anhingas could climb trees, but they can. Their webbed feet are equipped with powerful claws that let them climb from the ground up to their nests. Anhingas build their nests over water, but not high in a tree. They like to keep them low enough so they can climb up into them. This nest was located about 15 feet off the ground. We don't have Anhingas here in Cincinnati. They are a strictly a southeastern bird, so I don't get to spend a lot of time watching them and had never seen one climb up a tree. Within two weeks of hatching, baby Anhingas can fall out of the nest into the water below them. To get back to their nest, they climb up the trunk using their claws (source: Baughman, pg. 65).

Water Turkey!

Because an Anhinga's tail feathers resemble a turkey's with a striped pattern and a pale tip, they've been given the nickname of Water Turkey (very fitting for this time of year...).

Hanging the feathers out to dry...

Anhingas, like Cormorants, do not apply waterproofing oils to their feathers to make them waterproof. Instead, the unprotected feathers absorb water, which allows them to stay submerged and swim easily under water.

Feathers that absorb water lose their insulating properties, which causes Anhingas and Cormorants to lose body heat, so when we see them hanging their feathers out to dry, they are also using the sun's heat to stabilize their body temperature. Most of us already knew this, but what I didn't know was Anhingas have a very low metabolic rate and become chilled easily. They are dependent on the sun's heat to ward of hypothermia. As a result, they can spend up to a third of their daylight hours sunning (much more than a cormorant). It also explains why we often see Double-crested Cormorants in Ohio, but almost never see Anhingas (I've never seen an Anhinga in Ohio). An Anhinga's normal territory is the subtropical southeast (source: Baughman, pg. 65).

Snakebird!

Since the Anhinga's feathers are not waterproof, when they get wet, they look shiny and very smooth. When you couple that with a submerged body, a long skinny neck, and a slim head, instead of looking like a bird in the water, it looks like a black snake swimming along, which leads to its second nickname, Snakebird!

I took these photos on June 8, 2011 at the Ibis Pond rookery on Pinckney Island NWR in Hilton Head, SC, except for the last photo, which I took on March 22, 2011 at the Ding Darling NWR.

Video of a male Anhinga sitting on a nest showing gular fluttering in the heat.

I have never even heard of a such a bird - they are beautiful, and your photos are just amazing (as always). You do get to see a wonderful variety of birds, and thank you for sharing. I soooo enjoy your blog. I swear I learn something new every time I visit it!

Your images always take my breath away. I love the Anhinga and thanks to you, now see all their amazing colors. I had no idea of the coloring on their tails! Don't you just love their calligraphic necks?

I have often seen the anhingas drying their wings, but I haven't ever noticed their feet! It's surprising and a little amazing that they actually climb trees! I'll have to pay closer attention the next time I see one.

...thanks, everyone! What an incredible bird, and for me, until this summer, one I really only was able to see from afar. Up close the bird is stunning. The male's eye is red...it doesn't show up well enough in this photo, though. White the white bars and strips in the wing, he's very striking.

Exquisite photos and I so enjoyed reading more about this wonderful bird. I didn't know about their low metabolic rate, but that explains a lot! Anhingas are amazing creatures - thanks for giving us a great post about them!

My Camera and Lenses

I hand hold the camera for all my photos (I used to use a monopod or tripod for distance and macro, but the VR lenses don't seem to require it). I crop the images down in Aperture (I'm a Mac).

The Story Behind "Red and the Peanut"

Red and the Peanut is named after my first bird memory. When I was about six, I was at my Great Aunt Mary's house and she was telling me about Red and the peanut. "Red" was a Northern Cardinal that had trained Aunt Mary to feed it peanuts on demand. Since Aunt Mary's "Red" started it all, what better name could I choose?